首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   344篇
  免费   15篇
  国内免费   6篇
电工技术   59篇
综合类   48篇
化学工业   2篇
金属工艺   2篇
机械仪表   3篇
建筑科学   7篇
矿业工程   2篇
能源动力   1篇
无线电   141篇
一般工业技术   10篇
冶金工业   8篇
自动化技术   82篇
  2023年   1篇
  2022年   1篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2016年   2篇
  2015年   3篇
  2014年   13篇
  2013年   26篇
  2012年   18篇
  2011年   17篇
  2010年   20篇
  2009年   21篇
  2008年   15篇
  2007年   12篇
  2006年   14篇
  2005年   16篇
  2004年   14篇
  2003年   28篇
  2002年   27篇
  2001年   23篇
  2000年   13篇
  1999年   20篇
  1998年   10篇
  1997年   8篇
  1996年   10篇
  1995年   7篇
  1994年   4篇
  1993年   2篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1955年   1篇
排序方式: 共有365条查询结果,搜索用时 265 毫秒
41.
以波特的钻石模型为基础,借鉴国内外创新理论的相关研究成果,从成本要素、创新要素、同业竞争、相关支持产业、市场需求、政府相关政策及机会等方面,对我国电子及通讯装备制造业国际竞争力进行评价。研究结论认为:虽然中国电信设备和技术领域中已经出现具有较强的国际竞争力的龙头企业,但产业链发展不均衡将制约行业的整体发展。目前我国通讯制造企业在技术方面仍然处于跟随地位。由于中国整体劳动力成本的不断上升,以及在通讯基础专利技术占有较少的情况难以在短时期内改变,使得中国通讯产业的国际竞争优势面临挑战。  相似文献   
42.
运用灰色GM(1,1)模型,以北京市某运营商移动通信网络数据业务量为样本数据,通过模型预测的移动通信业务量的拟合数据与样本数据基本一致,得到的2020年业务量增长倍数在其他各家机构预测倍数范围之内,从而得出将灰色GM(1,1)模型用于移动通信数据业务量增长趋势的预测是合理的。  相似文献   
43.
代康 《现代传输》2014,(4):8-19
本文重点解读通信电源用交联聚烯烃绝缘电缆通信行业标准的主要内容,介绍了交联聚烯烃绝缘的技术特点.评述了聚氯乙烯(PVC)绝缘电缆在环保和安全方面存在的不足.通过比较说明了交联聚烯烃绝缘电缆相对于PVC绝缘电缆和非交联的无卤低烟阻燃聚烯烃绝缘电缆所具有的优势.本文还介绍了低压电缆制造技术,特别是交联工艺路线、电缆料添加剂及电缆料配混技术进展等方面的内容,对未来通信电源用电缆的发展以及标准修改内容提出了建议.  相似文献   
44.
Telecommunications in the US is undergoing a revolution. Corporations are attempting to leverage their competencies in the deregulated environment in order to enhance their competitive position. While the eventual results of this flurry of partnerships that has recently occurred are uncertain, there are certain trends that are becoming increasingly apparent. This paper represents an essay on the telecommunications industry (or its converging associated industries) and describes its history and evolving structure. Fifty-four partnerships are examined in an attempt to systematically examine an industry in transition. Key implications of these partnerships are also discussed.  相似文献   
45.
This paper investigates two kinds of strategic combinations carried out by the European telecom operators between 1986 and 2001: acquisitions, on the one hand, and strategic alliances, on the other. The aim of the paper is twofold. First, it analyzes the behavior adopted by these companies to adapt to an environment that, after the processes of globalization and privatization presents a clearly different structure. Second, it focuses on the effect that internationalization and diversification could exert over the returns obtained by the European telecom firms involved in acquisitions and alliances, differentiating when such strategic combinations are more profitable for the shareholders of the firms that carry them out.  相似文献   
46.
.Net Framework推出的许多新技术(比如Web Service)为建立可维护、可扩展的站点,开发高效率、高伸缩性的应用程序提供了相对简单的解决方案。本文介绍如何利用这些技术结合SQL Server数据存储技术或Xml文档创建N层分布式应用程序、实现跨平台、跨Internet的应用集成。  相似文献   
47.
本文列举了几个常被人们误译的英语电信名词,对词义和用法进行了探讨。  相似文献   
48.
This work discusses the evolution of W-LANs from their current status of wireless termination of LAN services to a possible global infrastructure where the access networks become open to multiple operators and a vehicle of a win-win scenario, where both users and operators benefit from the new network architecture. The idea of Open Access Networks (OANs) can go beyond wireless HotSpots and be generalized to a generic shared access infrastructure that fosters service operators competition and drastically reduces the cost of last mile coverage.The general concept of Open Access Networks is detailed, highlighting its difference with the more traditional model of vertical integration of the access network into the global service. About the OANs development, it is shown how to support the quick and smooth evolution of the infrastructure toward a widespread and reliable communication support.Business models are discussed by mentioning the different actors, the market organization and the different organization forms.The final part of the paper is devoted to technical challenges such as access control, security, privacy, roaming, resource exploitation and service differentiation. As an example of how to tackle these problems, we discuss a pricing technique devoted to resource management and billing support.In addition we present a simulation on how the OAN concept can speed-up the deployment of broadband access in a real case.A preliminary version of this paper with the title “Global Growth of Open Access Networks: from WarChalking and Connection Sharing to Sustainable Business” was presented at WMASH 2003. Roberto Battiti received the Laurea degree from the University of Trento, Italy, in 1985 and the Ph.D. degree from the California Institute of Technology (Caltech), USA, in 1990. He has been a consultant in the area of parallel computing and pattern recognition and since 1991 he has been a faculty member at the University of Trento, where he is now full professor of Computer Networks. His main research interests are heuristic algorithms for optimization problems, in particular reactive search algorithms for maximum clique, maximum satisfiability, graph coloring, networks and massively parallel architectures, code assignment in wireless and cellular networks, protocols for pricing and Quality of Service in wireless networks.Prof. R. Battiti is currently Dean of the international Graduate School in Information and Communication Technologies at Trento, Deputy Dean at the Faculty of Science, member of the advisory committee for the future Telecommunications Plan of the Autonomous Province of Trento. Prof. R. Battiti is associate editor of various scientific journals. He is the author of more than fifty scientific publications, including special issues dedicated to experimental algorithmics and wireless on-demand networks.R. Battiti is a member of IEEE Computer Society and ACM Sigmobile. Renato Lo Cigno is Associate Professor at the Department of Computer Science and Telecommunications (DIT) of the University of Trento, Italy. He received a Dr. Ing. degree in Electronic Engineering from Politecnico di Torino in 1988. From 1989 to 2002 has been with the Telecommunication Research Group of the Electronics Department of Politecnico di Torino.From June 1998 to February 1999, he was at the CS Department at UCLA as Visiting Scholar under grant CNR 203.15.8. He is coauthor of more than 90 journal and conference papers in the area of communication networks and systems. His curent research interests are in performance evaluation of wired and wireless networks, modeling and simulation techniques, flow and congestion control, as well as network management and architecture. Renato Lo Cigno is member of the IEEE Communication Society and ACM Sigcomm. Mikalai Sabel received his master degree in radio physics from Belorussian State University in 2002. He is now pursuing his Ph.D. at the international Graduate School of Information and Communication Technologies at University of Trento, Italy. His research interest include wireless LANs, pricing and incentive engineering, IEEE802.11 MAC protocol. His current research is focused on optimization algorithms that can provide stability and maximum global welfare in a non-cooperative environment where singles tries to maximize their own benefit function. Experimentation of such schemes to pricing techniques and micro-payments in TLC networks provides the application environment of the fundamental research. Fredrik Orava is associate professor at KTH, Stockholm, Sweden. He conducts research into scalable (in terms of cost, capacity, number of users and devices etc.) communication system architectures and technologies. He has a MSc in engineering physics from Uppsala University and a PhD in computer systems also from Uppsala University. He previously held positions as researcher at the Swedish Institute for Computer Science (SICS); senior lecturer and manager of the telecommunications systems laboratory at the department for teleinformatics, KTH; acting professor in telecomunication systems at KTH; director for the Swedish Centre for Internet Technologies; and vice president of Dynarc AB with world wide responsibility for product management. Dynarc AB develops, manufactures and sells IP routers for optical IP networks. Bjorn Pehrson is a professor of telecommunication systems at KTH, the Royal Institute of Technology in Stockholm, since 1992, where he has also served as a department chairman and vice dean. He had his PhD from Uppsala University 1975 where he also served as senior lecturer and established a research group in computer and communication technology. During the period 1985-1992 he participated in the establishment of the Swedish Institute of Computer Science. Björn Pehrson research interests are currently focussed on open network topologies allowing different actors forming new value chains to build networks together based on different, sometimes very local business models. The results are applied in testbeds, especially in rural areas and in developing countries.This revised version was published online in August 2005 with a corrected cover date.  相似文献   
49.
In the last ten years, the international telecommunications industry has undergone important changes from both the legislative (regulatory reforms) and the technological points of view. The liberalization of the telecommunications market has, consequently, affected the dynamics of the bilateral agreements between international carriers. In this paper, the international wholesale market in which carriers compete over the tariffs in order to increase their market share is analyzed. In particular, this paper examines the interactions between fixed telephony TLC carriers belonging to various countries and analyzes the possible strategic choices of the market leader induced by changes in competitor behavior.  相似文献   
50.
新型PLC-075电力线数据传输装置   总被引:6,自引:0,他引:6  
介绍了一种新型PLC-075电力线数据传输装置,阐述了基于虚拟载波帧测技术的多虚拟逻辑网络组网、增强型自适应模拟前端、自适应多频段收发、多耦合方式等关键技术;描述了其主要技术参数和应用于架空线和地埋电缆的不同耦合方式,给出了其在城市小区配电自动化中的具体应用实例.实践证明,该装置能有效地解决中压配电线传输特性的动态变化、突发干扰等难题,满足组网通信和实时性要求,可作为不同应用领域的低成本通信解决方案.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号